Background: Previous research suggests motion induced fatigue (MIF) contributes to significant performance degradation and is likely related to a higher incidence of accidents and injuries. However, the exact effect of continuous multidirectional platform perturbations on energy cost with experienced personnel on boats and other seafaring vessels remains unknown. Objective: The objective of this experiment was to measure the metabolic energy costs (EC) associated with maintaining postural stability in a motion-rich environment. Methods: Twenty volunteer participants, who were free of any musculoskeletal or balance disorders, performed three tasks while immersed in a moving environment that varied motion profiles similar to those experienced by workers on a mid-size commercial fishing vessel (static platform (baseline), low and high motions). Measures of ventilation were collected using a portable metabolic system that continuously measured breath-by-breath samples and heart rate using a wireless heart monitor. Results: Results indicate a systematic increase in metabolic costs associated with increased platform motions. The increases were most pronounced during the standing and lifting activities and were 50% greater during the high motion condition when compared to no motion. Increased heart rates were also observed. Discussion: Platform motions have a significant impact on metabolic costs that are both task and magnitude of motion dependent. Practitioners must take into consideration the influence of motion rich environments upon the systematic accumulation of operator fatigue.

The present study tested whether object specificity facilitates motor imagery whereas non-specificity disrupts motor imagery. We asked to a group of basketball players (experts) and a group of healthy controls (novices) to physically perform (motor execution) and mentally simulate (motor imagery) basketball free throws. Subjects produced motor imagery in three conditions: with-basketball, with-volleyball, and without-ball. The temporal congruence between motor execution and motor imagery as well as the vividness of motor imagery were evaluated. Results showed that experts produced greater temporal congruence and vividness of kinesthetic imagery in the with-basketball condition compared to the without-ball condition, suggesting a facilitation effect from action-specific objects. In contrast, experts produced lower temporal congruence and vividness of kinesthetic imagery in the with-volleyball condition compared to without-ball condition, suggesting the interference effect of non-specific objects. Furthermore, we found a negative correlation between temporal congruence and the vividness of kinesthetic imagery in experts in the with-basketball condition. On the contrary, the object manipulation did not modulate the temporal congruence of novices. Our findings suggest that motor representation in experts is built on object-specific motor experience and thus was subject to modulation of the object held. We conclude that action-specific objects facilitate motor imagery whereas non-specific objects could disrupt motor representation in experts.

Background. As the start of table tennis playing, serve involves complex spatial movement with biomechanial characteristics . Although the differences in lower-limb biomechanial characteristics to a great extent influence the translational and spinning velocity of the ball when using the different styles of table tennis serve, few researchers have studied their mechanics. Therefore, the aim of this study was to investigate the differences in lower-limb activity between squat and standing services during a table tennis short serve.

Methods. Six advanced female table tennis participants performed a squat serve and standing serve in random order. A Vicon motion analysis system and a Novel Pedar insole plantar pressure measurement system were used to record kinematics and kinetics data, respectively.

Results. Key findings from the study were that the squat serve not only showed significantly larger hip and knee flexion, as well as ankle dorsiflexion, it also showed significantly larger hip adduction and external knee rotation, with changing angular rate of the lower limb joints when the two serving styles were compared. In addition, relative loads were higher in the rear foot area for the standing serve.

Discussion. The results demonstrated that the squat serve needs higher lower limb drive during a table tennis short serve compared with a standing serve. These biomechanical considerations would be beneficial for table tennis athletes and coaches to optimize performance characteristics during both competition and training.

Subject areas

FAQs

Is this open peer review?

No, peer review is still single-blind and all recommendations are private between the authors and Academic Editor. However, any reviewer has the option to sign their report, and once accepted for publication then that review can be shown publicly - again this is optional.

Will I be guaranteed to review if I volunteer?

No. Volunteering is not a guarantee that you will be asked to review. This is for many reasons. For one, reviewers must have relevant qualifications for any manuscript and void of any conflicts of interest. Additionally, it could be that enough reviewers have accepted an invitation to review already, in which case we would not invite any more.

Why aren't there more manuscripts available?

Manuscripts are shown when authors have opted-in for obtaining reviewers through the reviewer-match service. Additionally, there may already be enough reviewers found through other means, for example, invitations sent by the Academic Editor in charge.

What are the editorial criteria?

Please visit the editorial criteria page for initial guidance. You will also be given additional information if invited to review.